高强度聚焦超声消融靶区表面的损伤研究

Damage research of targeted region in high intensity focused ultrasound circumferential ablation

目的:探讨高强度聚焦超声(high intensity focused ultrasound,HIFU)消融靶区表面损伤的方法及表面消融模式的优势。方法:以离体牛肝为研究对象,分成3组,单点消融组辐照结束后与仿真计算的牛肝坏死形态、大小进行比较分析。表面消融组和完全消融组以相同的组合参数,在不同深度处动态调节辐照声强进行消融实验,对两组的辐照时间及累积能量进行统计分析。表面消融后采集超声二维图像测量分析并重建靶区,测量的损伤区域与病理测量区域对比分析。结果:HIFU单点辐照损伤大小与理论值相差不大。表面消融模式能在靶区周边形成完整的坏死带,在超声图像上呈强回声,靶区3D重建图像较清晰。两种模式的总辐照时间与累积能量比较均有显著统计学差异(P<0.05);超声图像勾画和牛肝组织坏死测量的消融体积平均值比较无统计学差异(P>0.05)。结论:超声影像学能实时监控HIFU表面消融模式所致的靶组织坏死区域,HIFU表面消融模式可提高消融效率,缩短辐照时间。

Objective：To investigate the method of damage in target region and the advantages of high intensity focused ultrasound（HIFU）circumferential ablation. Methods：Bovine liver was taken as the research object and was divided into three groups. Both simulation calculation and experimental results were compared to observe the shape and size of necrosis volume in single exposure group after the irradiation. The same irradiation parameters were used and the irradiation intensity was dynamically adjusted at different depths to complete ablation experiments. Irradiation time and energy accumulation were analyzed in the experiments. Two-dimensional ultrasound images were collected after circumferential ablation;the ablated area with hyperechoic changes was measured and reconstructed,and compared with the macroscopic measurement of coagulation necrosis in the liver. Results：There was no obvious difference in the area and volume of coagulation necrosis between theoretical simulation and experimental results. A complete necrosis around the circumferential region of the targeted liver was observed in circumferential ablation,and an obvious hyperechoic change was observed on ultrasound imaging. The 3D reconstruction of ultrasound images in the treated region was established,and the margin was easily identified between the treated and untreated areas. Total irradiation time and total energy accumulation were significantly different between the two ablation modes（P〈0.05）. No statistical difference was observed between two measurements（P〈0.05）.Conclusion：Real-time ultrasound imaging can monitor volume of the target in circumferential HIFU ablation procedure. Circumferential HIFU ablation mode can improve the efficiency of ablation,shorten the time of irradiation.